Wing fold system rotating latch

ABSTRACT

An apparatus and method of a wing fold system may include a latch assembly rotating an unfixed portion of a wing, with respect to a fixed portion of the wing, between a flight position of the wing and a folded position of the wing. A first portion of the wing may hold a rotating portion of the latch assembly. A second portion of the wing may hold a secured portion of the latch assembly. The rotating portion of the latch assembly may rotate between an open position and a closed position. A slot in the rotating portion may receive the secured portion of the latch assembly. A securing portion of the rotating portion may secure a secured portion of the latch assembly. The latch assembly may prevent rotation of the second portion when the wing may be in the flight position.

CROSS REFERENCE AND PRIORITY

This application is a divisional application of U.S patent applicationSer. No. 13/966,754, filed Aug. 14, 2013, and issued as U.S Pat. No.9,469,392 issued Nov. 18, 2016, which claims the benefit of ProvisionalU.S. Patent Application No. 61/720,328, filed Oct. 30, 2012, the entiredisclosure of which is incorporated by reference herein.

FIELD OF THE DISCLOSURE

This disclosure relates to systems and methods for providing wings, andmore specifically, to systems and methods for latching wings thatenhance aircraft performance.

BACKGROUND OF THE DISCLOSURE

In today's commercial transport industry, it is highly desirable todesign aircraft configurations that yield reduced fuel burn perseat-mile, as fuel burn per seat-mile is a metric of fuel efficiency.Efficient aircraft configurations are ever more important as fuel costscontinue to increase. Aircraft aerodynamic drag and fuel burn aregenerally reduced as the aspect ratio of the aircraft wing increases.Similarly, operating larger aircraft which carry more passengers andpayload is generally more efficient between two destinations than flyingseveral trips with smaller aircraft. Thus larger aircraft and aircraftwith longer wingspans tend to be more efficient. However, taxiwayspacing and gate locations for most airports were established withoutproviding adequate spacing for aircraft with longer wingspans that canbe produced with today's technology.

Some attempts have been made to improve aircraft wing efficiency withoutadding wingspan. Winglets extending vertically from the wingtips haveimproved aircraft fuel efficiency without significantly increasingwingspan. However, the efficiency added by winglets is not as beneficialas that provided by extending the wingspan.

Some military aircraft have folding wings to reduce space needed tostore the aircraft. Current wing folding designs contain features thatadd significant weight and/or drag to the wing of an aircraft.

Thus it is desired to provide an aircraft that can benefit from a longwingspan in flight, while being able to reduce the wingspan whenoperating at an airport, utilizing a system and method without weightand drag penalties of current folding wing aircraft.

SUMMARY

Some illustrative embodiments may provide for a method of latching afolding wing that may include a latch assembly of a wing fold systemrotating an unfixed portion of a wing with respect to a fixed portion ofthe wing between a flight position of the wing and a folded position ofthe wing. A first portion of the wing may hold a rotating portion of thelatch assembly. A second portion of the wing may hold a secured portionof the latch assembly. A slot of the rotating portion may receive thesecured portion. The rotating portion of the latch assembly may rotatebetween an open position and a closed position. A securing portion ofthe rotating portion may secure a secured portion of the latch assemblywhen the rotating portion may be in the closed position. The latchassembly may prevent rotation of the second portion when the wing may bein the flight position.

Some illustrative embodiments may provide for an apparatus of a wingfold system that may include a fixed portion of a wing, an unfixedportion of the wing, a first portion of the wing, a second portion ofthe wing, and a latch assembly. The unfixed portion of the wing mayrotate between a folded position of the wing and a flight position ofthe wing. The first portion of the wing may hold a rotating portion of alatch assembly of the wing. The second portion of the wing may hold asecured portion of the latch assembly of the wing. The latch assemblymay prevent rotation of the unfixed portion of the wing. The rotatingportion of the latch assembly may rotate between an open position and aclosed position. The rotating portion may include a securing portion anda slot. The securing portion of the rotating portion secures the securedportion of the latch assembly when in the closed position. The slot ofthe rotating portion may receive the secured portion of the latchassembly when in the open position.

The features and functions can be achieved independently in variousembodiments of the present disclosure or may be combined in yet otherembodiments in which further details can be seen with reference to thefollowing description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the illustrativeembodiments are set forth in the appended claims. The illustrativeembodiments, however, as well as a preferred mode of use, furtherobjectives and features thereof, will best be understood by reference tothe following detailed description of an illustrative embodiment of thepresent disclosure when read in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a diagram of an aircraft embodying a wing fold system in aflight position in accordance with an illustrative embodiment;

FIG. 2 is a diagram of an aircraft embodying a wing fold system in afolded position in accordance with an illustrative embodiment;

FIG. 3 is a block diagram of a wing with a rotating latch in accordancewith an illustrative embodiment;

FIG. 4 is a block diagram of a latch assembly configured as a barrellatch in accordance with an illustrative embodiment;

FIG. 5 is a block diagram of a latch assembly configured as a hook latchin accordance with an illustrative embodiment;

FIG. 6 is a block diagram of a latch assembly configured as a bear clawlatch in accordance with an illustrative embodiment;

FIG. 7 is a block diagram of a latch assembly configured as a cam latchin accordance with an illustrative embodiment;

FIGS. 8A-8B are diagrams of a folding wing including a latch assembly inaccordance with an illustrative embodiment; FIG. 8A, is a diagram of thefolding wing in a flight position with the latch assembly in a closedposition in accordance with an illustrative embodiment; FIG. 8B is adiagram of the folding wing in a folded position, with the latchassembly in an open position in accordance with an illustrativeembodiment;

FIG. 9 is a diagram of a wing with a barrel latch, the wing almost in aflight position, the barrel latch in an open position, and a lock of thebarrel latch in a disengaged position, in accordance with anillustrative embodiment;

FIG. 10 is a diagram of a wing with a barrel latch, the wing not in aflight position, and the barrel latch in an open position, in accordancewith an illustrative embodiment;

FIG. 11 is a diagram of a wing with a barrel latch, the wing in a flightposition, the barrel latch in an open position, and a lock of the barrellatch in a disengaged position, in accordance with an illustrativeembodiment;

FIG. 12 is a diagram of a wing with a barrel latch, the wing in a flightposition, the barrel latch in a closed position, and a lock of thebarrel latch in an engaged position, in accordance with an illustrativeembodiment;

FIG. 13 is a diagram of a perspective view from above looking aft insidea cutaway of a wing with a hook latch, the wing in a flight position,and the hook latch in a closed position, in accordance with anillustrative embodiment;

FIG. 14 is a diagram of a perspective view from above looking aft insidea cutaway of a wing with a hook latch, zoomed in on one-half of FIG. 13,the wing not in a flight position, and the hook latch in an openposition, in accordance with an illustrative embodiment;

FIG. 15 is a diagram of a perspective view from above looking aft insidea cutaway of a wing with a hook latch, zoomed in on one-half of FIG. 13,the wing in a flight position, and the hook latch in an open position,in accordance with an illustrative embodiment;

FIG. 16 is a diagram of a perspective view from above looking aft insidea cutaway of a wing with a hook latch, zoomed in on one-half of FIG. 13,the wing in a flight position, and the hook latch in an closed position,in accordance with an illustrative embodiment;

FIGS. 17A-17B are diagrams of a side view of a hook latch for a foldingwing, in accordance with an illustrative embodiment; FIG. 17A is adiagram of a side view of a hook latch for a folding wing in transitionbetween an open position and a closed position, with a lock of the hooklatch in a disengaged position, in accordance with an illustrativeembodiment; and FIG. 17B is a diagram of a side view of a hook latch fora folding wing in the closed position, with a lock of the hook latch inan engaged position, in accordance with an illustrative embodiment;

FIG. 18 is a diagram of a wing with a bear claw latch, the wing almostin a flight position, the bear claw latch in an open position, and alock of the bear claw latch in a disengaged position, in accordance withan illustrative embodiment;

FIG. 19 is a diagram of a wing with a bear claw latch, the wing in aflight position, the bear claw latch in an open position, and a lock ofthe bear claw latch in a disengaged position, in accordance with anillustrative embodiment;

FIG. 20 is a diagram of a wing with a bear claw latch, the wing in aflight position, the bear claw latch in a closed position, and a lock ofthe bear claw latch in a disengaged position, in accordance with anillustrative embodiment;

FIG. 21 is a diagram of a wing with a bear claw latch, the wing in aflight position, the bear claw latch in a closed position, and a lock ofthe bear claw latch in an engaged position, in accordance with anillustrative embodiment;

FIG. 22 is a diagram of a perspective upward looking view of a cam latchin an open position, and a lock of the cam latch in a disengagedposition, in accordance with an illustrative embodiment;

FIG. 23 is a perspective upward looking view diagram of a cam latch inan open position for a wing in a flight position, and a lock of the camlatch in a disengaged position, in accordance with an illustrativeembodiment;

FIG. 24 is a perspective upward looking view diagram a cam latch in aclosed position for a wing in a flight position, and a lock of the camlatch in a disengaged position, in accordance with an illustrativeembodiment;

FIG. 25 is a perspective upward looking view diagram a cam latch in aclosed position for a wing in a flight position, and a lock of the camlatch in an engaged position, in accordance with an illustrativeembodiment;

FIG. 26 is a diagram of operations for a method of folding and unfoldinga wing, depicted in accordance with an illustrative embodiment; FIG. 26shows operation 2602 through operation 2620;

FIG. 27 is an illustration of an aircraft manufacturing and servicemethod is depicted in accordance with an illustrative embodiment; and

FIG. 28 is an illustration of an aircraft is depicted in which anillustrative embodiment may be implemented.

DETAILED DESCRIPTION

The illustrative embodiments described below may provide for a wing foldsystem within a wing and a method of folding a wing that may increasethe fuel efficiency of an aircraft while precluding any increase in ashape and/or thickness of, and/or adding a fairing to, a wing shape thatmay not incorporate a wing fold system. The illustrative embodimentsbelow may describe systems or methods that provide latching of a foldingwingtip with less excrescence drag, lower manufacturing cost and betterreliability than existing designs. Typical current folding wingtip latchpins and associated actuators may require large spatial integrationvolume. Typical current folding wingtip mechanisms often protrudeoutside the wing surface, and require a fairing, which adds drag.

By contrast the methods and systems illustrated below may be morecompact than those used in current folding wings, and may eliminate aneed for any wing fairing. The method and systems disclosed may precludeexpansion of a wing shape when incorporating the wing fold system intothe wing. Thus, a wing may gain an ability to fold, without changing across-sectional outline of the wing. Existing pin-in-lug designsgenerally require close tolerance and expensive dimensional control.Existing pin-in-lug designs require more maintenance than the systemsand methods illustrated below. Existing pin-in-lug designs sufferfailures to insert or retract.

Systems and methods illustrated below may allow looser dimensionaltolerances, which afford reduced maintenance down time and costs.Systems and methods illustrated below may provide more latching surfacearea in contact, may better distribute torsional loads, may incorporatelocking mechanisms and over center locking design features as well aslocking mechanisms, may provide greater component reliability andredundancy, with less volume and weight than existing wing foldmechanisms. Further, components of the methods and systems illustratedbelow may be easier to access and replace than those of current wingfold designs.

Illustrative embodiments may recognize and take account of one or moredifferent considerations. For example, having an aircraft that maybenefit from a long wingspan in flight, while being able to reduce thewingspan when operating at an airport, such as but not limited toInternational Civil Aviation Organization “code E” airports, isdesirable with respect to increasing the flexibility of where anaircraft may operate. In particular, by being able to reduce thewingspan while on the ground, an aircraft may be able to operate at moreairports than if the aircraft could not reduce its wingspan while on theground. With the longer wingspan during flight, benefits may includefuel efficiency.

Thus, control of the wingspan of an aircraft may be advantageouslyachieved through the use of a wing fold system. The wing fold system maytransition an unfixed portion of a wing between a folded position and aflight position, therein controlling the wingspan of the aircraft.

The illustrative embodiments may allow for automated folding andextending of wingtips based on location of aircraft during preparationfor takeoff or after landing. Architecture provided herein may includean wingtip folding system that may allow for increased aircraftreliability based in part on redundant system components. The system maybe more adaptive to automated operation than current wing fold designs.

The illustrative embodiments may promote more ease in modification towingtip folding functionality. Such functionality may includemodification of software code as opposed to altering mechanical hardwareand kinematic interfaces. Diagnostic capability of the wingtip systemmay include earlier detection of vulnerable components which may reducetime of exposure to latent vulnerabilities.

The system may be less subject to dynamic mechanical feedback. Theillustrative embodiments may promote greater ease in verifyingfunctionality of the system, allowing for checks of the system forpossible latent problems via automated, periodic system tests. Forexample, the system may verify that a moveable wingtip is latched orlocked to a fixed wingtip.

The illustrative embodiments may promote a reduced workload on crew.Minimal or no crew actions may be required to configure wingtips forflight or ground operations including taxiway and gate operations.Location-based alerting may also be promoted. Prior to takeoff, thesystem may verify that the aircraft is in flight worthy configurationbefore engine thrust may be applied. After landing, the system mayverify that the aircraft is in a correct configuration for taxiway,runway, gate and maintenance facility operations.

The illustrative embodiments may provide improvements over previous wingcontrol arrangements that may require large spatial integration volume.Such previous requirements may result in increased wing thickness thatmay cause excess drag and greater weight. Previous designs also may notbe readily modified or optimized once their designs are finalized as maybe possible with embodiments illustrated below.

By contrast, the illustrative embodiments may provide a more electricaland optical control system as compared to previous hydraulic andmechanical heavy designs. Improved folding designs may allow for lessrequired force to move the unfixed portion of the wing, and enable useof less powerful actuators. Less powerful actuators may be smallerand/or lighter than current actuators. Less powerful actuators may beelectric in place of previously used hydraulic actuators. Theillustrative embodiments may reduce component volume and allow foroptimization and modification via software updates. Further, theillustrative embodiments may alleviate concerns over lightning strikesand electromagnetic effects when considering optical signaltransmission. A more electric architecture may allow for easier buildand maintainability of aircraft through installation of replaceablecomponents as opposed to mechanical components that may requireindividual shimming and rigging.

Unless otherwise noted and where appropriate, similarly named featuresand elements of illustrative embodiments of one figure of the disclosurecorrespond to and embody similarly named features and elements ofembodiments of the other figures of the disclosure. With reference nowto the figures, and in particular, with reference to FIGS. 1 and 2,FIGS. 1 and 2 are diagrams of an aircraft depicted in accordance withillustrative embodiments. Aircraft 100 may be an example of an aircraftin which a wing fold system may be implemented in accordance with anillustrative embodiment. In this illustrative example, aircraft 100 mayinclude wing 102 and wing 104 attached to body 106; engine 108 attachedto wing 102; and engine 110 attached to wing 104. FIG. 1 depicts wings102 and 104 of aircraft 100 in flight position 302 of FIG. 3 and FIG. 2depicts wings 102 and 104 of aircraft 100 in folded position 304 of FIG.3.

Wing 102 may include a fixed portion 124 and an unfixed portion 120.Fixed portion 124 may be an inboard portion of the wing fixed to body106. Similarly, wing 104 may include a fixed portion 126 and an unfixedportion 122. Wing 102 may include wing fold system 130 that may moveunfixed portion 120 with respect to fixed portion 124. Wing 104 mayinclude wing fold system 128 that may move unfixed portion 122 withrespect to fixed portion 126. FIG. 1 shows wing fold system 128 and 130of aircraft 100 in flight position 302, with wingspan 132 such thataircraft 100 may be ready for flight. FIG. 2 shows wingspan 202, reducedfrom wingspan 132, for operation at an airport.

Body 106 may connect to tail section 112. Horizontal stabilizer 114,horizontal stabilizer 116, and vertical stabilizer 118 may be attachedto tail section 112 of body 106.

Aircraft 100 may be an example of an aircraft in which a wing foldsystem may be implemented in accordance with an illustrative embodiment.Wing fold system 128 and wing fold system 130 each may include a latchassembly in accordance with an illustrative embodiment.

With reference to FIG. 3, FIG. 3 is a block diagram of a wing with arotating latch in accordance with an illustrative embodiment. Wing 300may be an illustrative embodiment of wing 102 and/or wing 104 in FIG. 1.Wing 300 may include flight position 302, folded position 304, fixedportion 306, unfixed portion 310, first portion 314, second portion 318,and latch assembly 322. A folding capability of wing 300 may allow foraircraft 100 to be flown with wingspan 132, as shown in FIG. 1, that maybe longer than wingspan 202, as shown in FIG. 2, that may be allowed forground operation at an airport. Wing 300 may provide lift for aircraft100 in FIG. 1.

Flight position 302 may be a state of wing 300. When an aircraft's wingsmay be in flight position 302, the aircraft may be ready for flight.Wing 102 and wing 104 of FIG. 1 are in a flight position, such as flightposition 302 of FIG. 3. A latch may close to secure wing 300 in flightposition 302 and a lock may engage the latch to ensure wing 300 stays inflight position 302.

Folded position 304 may be a state of wing 300. When wings of aircraft100 may be in folded position 304, aircraft 100 is not ready for flight,but the overall wingspan of aircraft 100 may be sufficiently small toallow use of aircraft 100 at airports that require smaller overallwingspan.

Fixed portion 306 may be an embodiment of fixed portion 124 of wing 102and an example of an embodiment of fixed portion 126 of wing 104 inFIG. 1. Fixed portion 306 of wing 300 may include wing box 308, moveablecontrol surfaces 338, and fold actuator 340. Wing box 308 is astructural component that may be comprised by wing 300. Moveable controlsurfaces 338 may include flaps that allow for controlling flight ofaircraft 100.

Unfixed portion 310 may be an example of an embodiment of unfixedportion 120 of wing 102 and an embodiment of unfixed portion 122 of wing104 in FIG. 1. Unfixed portion 310 may rotate with respect to fixedportion 306 of wing 300 between flight position 302 of wing 300 andfolded position 304 of wing 300. Unfixed portion 310 of wing 300 mayinclude wingtip 312. Wingtip 312 may not include moveable controlsurfaces 338.

First portion 314 of wing 300 may be one of fixed portion 306 andunfixed portion 310. Second portion 318 of wing 300 may be the other offixed portion 306 and unfixed portion 310. First portion 314 may includerotating portion 316 of latch assembly 322. First portion 314 mayconnect rotating portion 316 of latch assembly 322 to wing 300. Secondportion 318 may include secured portion 320 of latch assembly 322 towing 300. Second portion 318 may connect secured portion 320 of latchassembly 322 to wing 300.

Latch assembly 322 may include open position 334, closed position 336,rotating portion 316, secured portion 320, lock 326, and latch actuator342. Latch assembly 322 may prevent rotation of unfixed portion 310.Rotation of unfixed portion 310 may be prevented when wing 300 is inflight position 302. Latch assembly 322 may allow rotation of unfixedportion 310. Unfixed portion 310 may be rotated to folded position 304for operations when aircraft 100 is not in flight.

Open position 334 may allow unfixed portion 310 of wing 300 totransition to flight position 302. Closed position 336 may preventunfixed portion 310 from moving with respect to fixed portion 306.Second portion 318 may be latched in secured portion 320 when latchassembly 322 is in closed position 336. When latch assembly 322 is inclosed position 336, lock 326 may transition between engaged position330 and disengaged position 332.

Rotating portion 316 may include slot 324 and securing portion 328.Rotating portion 316 of latch assembly 322 may rotate between openposition 334 and closed position 336. Latch actuator 342 may moverotating portion 316. Securing portion 328 may secure secured portion320 of latch assembly 322 when rotating portion 316 is in closedposition 336. Slot 324 may receive secured portion 320 when rotatingportion 316 is in open position 334 or when rotating portion 316 maytransition between open position 334 and closed position 336.

Secured portion 320 may be attached to second portion 318. Securedportion 320 may be received by slot 324 of rotating portion 316 whenrotating portion 316 is in open position 334 or when rotating portion316 transitions between open position 334 and closed position 336.Secured portion 320 may be secured by securing portion 328 of rotatingportion 316 when rotating portion 316 is in closed position 336.

Lock 326 may include engaged position 330 and may include disengagedposition 332. Lock 326 may engage rotating portion 316 of latch assembly322 when rotating portion 316 is in closed position 336. Lock 326 mayprevent rotation of rotating portion 316 of latch assembly 322 when lock326 is engaged with rotating portion 316.

Engaged position 330 of lock 326 may prevent rotating portion 316 frommoving when rotating portion 316 is in closed position 336. Disengagedposition 332 of lock 326 may allow rotating portion 316 to transitionbetween open position 334 and closed position 336.

With reference to FIG. 4, FIG. 4 is a block diagram of a latch assemblyconfigured as a barrel latch in accordance with an illustrativeembodiment. Barrel latch 402 is an embodiment of latch assembly 322 ofFIG. 3. Barrel latch 402 may prevent rotation of an unfixed portion,such as unfixed portion 120, unfixed portion 122, and unfixed portion310 of FIGS. 1, 2, and 3; of a wing, such as wing 102, wing 104, andwing 300 of FIGS. 1, 2, and 3.

Barrel latch 402 may include secured portion 404, rotating portion 406,and lock 408. Secured portion 404 may be an example of an embodiment ofsecured portion 320 of FIG. 3.

Secured portion 404 may include T-shaped end 410. Secured portion 404may be connected to a set of inner lugs 436 attached to second portion318 of wing 300 of FIG. 3. T-shaped end 410 may be received by slot 412of rotating portion 406, when rotating portion 406 may be in openposition 334. T-shaped end 410 of secured portion 404 may be secured bysecuring portion 414 of rotating portion 406 when rotating portion 406may be in closed position 336.

Rotating portion 406 may be an example of an embodiment of rotatingportion 316 of FIG. 3. Rotating portion 406 may be connected to a set ofouter lugs 434 attached to first portion 314 of wing 300 of FIG. 3.Rotating portion 406 may rotate between open position 334 and closedposition 336. Rotating portion 406 may include barrel 418.

Barrel 418 may include slot 412, securing portion 414, and notch 420.Barrel 418 may be cylindrically shaped. Barrel 418 may be rotated bybarrel actuator 430. Barrel actuator 430 may be an example of anembodiment of latch actuator 342 of FIG. 3. Slot 412 of barrel 418 mayreceive T-shaped end 410 of secured portion 404 when rotating portion406 may be in open position 334. Securing portion 414 of barrel 418 maysecure secured portion 404 of barrel latch 402 when rotating portion 406may be in closed position 336. Notch 420 of barrel cylindrically shapedbarrel 418 may engage lock 408.

Lock 408 may include: lock actuator 422, rod lug 424, rod 426, and arm428. Lock actuator 422 may be connected to rod lug 424, which may beconnected to rod 426, which may be connected to arm 428.

Extension of lock actuator 422 may rotate rod lug 424 upward away frombarrel 418. Rod lug 424 rotating away from barrel 418 may rotate rod 426in the same direction as rod lug 424. Rotating rod 426 in the samedirection as rod lug rod lug 424 may move arm 428 upward away from anycontact with barrel 418.

Arm 428 may also be moved into contact with notch 420 when lock actuator422 retracts. When lock actuator 422 retracts, rod lug 424 may be pulleddown toward barrel 418, and rod 426 may rotate in the same direction asrod lug 424. Rod 426 rotating in the same direction as rod lug rod lug424 may move arm 428 downward and arm 428 may contact barrel 418.

When barrel 418 may be in closed position 336, notch 420 may be inposition that may receive arm 428. Notch 420 may be an open section inan end portion of barrel 418. Arm 428 may engage with barrel 418 in amanner that may prevent rotation of barrel 418.

Arm 428 may include target 432. Target 432 may extend from arm 428. Asensor may detect target 432 when arm 428 may be engaged in notch 420.

If arm 428 is moved to contact barrel 418 while barrel 418 is in openposition 334, then arm 428 may not engage notch 420. If arm 428 does notengage notch 420, then arm 428 may not restrict rotation of barrel 418.

Rod 426 may connect to more than one arm 428. More than one arm 428connected to rod lug 424 may provide redundancy for locking barrel 418against rotation from closed position 336 to open position 334.

With reference to FIG. 5, FIG. 5 is a block diagram of a latch assemblyconfigured as a hook latch in accordance with an illustrativeembodiment. Hook latch 502 may be an example of an embodiment of latchassembly 322 of FIG. 3. More specifically, hook latch 502 may preventrotation of an unfixed portion, such as unfixed portion 120, unfixedportion 122, and unfixed portion 310 of FIGS. 1, 2, and 3; of a wing,such as wing 102, wing 104, and wing 300 of FIGS. 1, 2, and 3; and of anaircraft, such as aircraft 100 of FIGS. 1 and 2. Hook latch 502 mayinclude secured portion 504, rotating portion 506, and hook actuator516.

Secured portion 504 may be an embodiment of secured portion 320 of FIG.3. Secured portion 504 may be attached to a second portion of a wing ofan aircraft, such as second portion 318 of wing 300 of FIG. 3. Securedportion 504 may include latch bar 508 that may be received by slot 510of rotating portion 506 when rotating portion 506 transitions betweenopen position 334 and closed position 336. Latch bar 508 of securedportion 504 may be secured by securing portion 512 of rotating portion506 when rotating portion 506 is in closed position 336.

Rotating portion 506 may be an example of an embodiment of rotatingportion 316 of FIG. 3. Rotating portion 506 may include slot 510,securing portion 512, and rotation bar 514. Rotating portion 506 mayrotate between open position 334 and closed position 336.

Rotation bar 514 may include lug 520. Lug 520 may be moved by hookactuator 516. Lug 520 moving may rotate rotation bar 514 and engage hook518 of securing portion 512 with latch bar 508 of secured portion 504.Rotation bar 514 may be connected to one or more securing portion 512,and to one or more hook 518. Each rotating portion 506 may have one ormore hook 518. Rotation bar 514 may be used to rotate a group of atleast one hook 518 in embodiments that may use multiple hooks.

Securing portion 512 may be an example of an embodiment of securingportion 328 of FIG. 3. Securing portion 512 may include hook 518.Securing portion 512 may secure latch bar 508 of secured portion 504 ofhook latch 502 when rotating portion 506 is in closed position 336.

Slot 510 of rotating portion 506 may receive secured portion 504 whenrotating portion 506 transitions between open position 334 and closedposition 336. Hook 518 may engage latch bar 508 of secured portion 504to prevent rotation of unfixed portion 310 of wing 300.

Using more than one rotating portion 506, with each rotating portionhaving its own securing portion 512, and each securing portion havingits own hook 518 may provide redundancy in securing the rotating portion506 to the secured portion 504 in the event that one or more of therotating portion 506 are unable to engage the secured portionsufficiently to keep hook latch 502 in closed position 336.

With reference to FIG. 6, FIG. 6 is a block diagram of a latch assemblyconfigured as a bear claw latch in accordance with an illustrativeembodiment. Bear claw latch 602 is an embodiment of latch assembly 322of FIG. 3. Bear claw latch 602 may prevent rotation of an unfixedportion, such as unfixed portion 120, unfixed portion 122, and unfixedportion 310 of FIGS. 1, 2, and 3; of a wing, such as wing 102, wing 104,and wing 300 of FIGS. 1, 2, and 3; and of an aircraft, such as aircraft100 of FIGS. 1 and 2. Bear claw latch 602 may include secured portion604, rotating portion 606, and claw actuator 608.

Secured portion 604 may be an example of an embodiment of securedportion 320 of FIG. 3. Secured portion 604 may be attached to a secondportion, such as second portion 318 of wing 300 of FIG. 3. Securedportion 604 may include group of openings 610, alignment gaps 612, andnub gap 614.

Group of openings 610 may receive group of hooks 616 of securing portion618 of rotating portion 606 when rotating portion 606 transitionsbetween open position 334 and closed position 336. Secured portion 604may be secured by group of hooks 616 of securing portion 618 of rotatingportion 606 when rotating portion 606 is in closed position 336.

Rotating portion 606 may be an example of an embodiment of rotatingportion 316 of FIG. 3. Rotating portion 606 may include, securingportion 618, rotation bar 620, slot 622, and base 624. Rotating portion606 may rotate between open position 334 and closed position 336.

Base 624 may include torsion nub 626. Torsion nub 626 may engage nub gap614 of secured portion 604 when bear claw latch 602 is in closedposition 336.

Rotating portion 606 may be rotated by claw actuator 608. Claw actuator608 may move rotating portion 606, may rotate group of hooks 616. Movingrotating portion 606 may engage group of hooks 616 of securing portion618 with group of openings 610 of secured portion 604. Group of hooks616 may be formed as a single unit. Rotation bar 620 may allow securingportion 618 to rotate about base 624.

Securing portion 618 may be an example of an embodiment of securingportion 328 of FIG. 3. Securing portion 618 may secure secured portion604 to rotating portion 606. Rotating portion 606 may be in closedposition 336 when securing portion 618 may secure secured portion 604 torotating portion 606. Slot 622 of rotating portion 606 may receivesecured portion 604. Rotating portion 606 may enter slot 622 whenrotating portion 606 transitions from open position 334 to closedposition 336.

Securing portion 618 may include group of hooks 616. Group of hooks 616may engage group of openings 610 of secured portion 604. Group of hooks616 engaging group of openings 610 of secured portion 604 may preventrotation of unfixed portion 310 of wing 300. Rotation of unfixed portion310 of wing 300 may be undesirable when wing 300 may be in flightposition 302, such as when an aircraft is in flight.

With reference now to FIG. 7, FIG. 7 is a block diagram of a latchassembly configured as a cam latch in accordance with an illustrativeembodiment. More specifically, Cam latch 702 may be an example of anembodiment of latch assembly 322 of FIG. 3.

Cam latch 702 may include secured portion 704 and rotating portion 706,cam actuator 720 and lock 722. Cam latch 702 may prevent rotation of anunfixed portion, such as unfixed portion 120, unfixed portion 122, andunfixed portion 310 of FIGS. 1, 2, and 3; of a wing, such as wing 102,wing 104, and wing 300 of FIGS. 1, 2, and 3; and of an aircraft, such asaircraft 100 of FIGS. 1 and 2.

Secured portion 704 may be an example of an embodiment of securedportion 320 of FIG. 3. Secured portion 704 may be attached to secondportion 318 of wing 300. Secured portion 704 may include group ofopenings 708 that is received by slot 710 in cam 712 of rotating portion706 when rotating portion 706 is in open position 334, as shown in FIG.3. Each opening in group of openings 708 may be semicircular. Cam 712may be cylindrical. Group of openings 708 of secured portion 704 may besecured by securing portion 718 of rotating portion 706 when rotatingportion 706 is in closed position 336, as shown in FIG. 3.

Rotating portion 706 may include cam 712 and securing portion 718.Rotating portion 706 may be an example of an embodiment of rotatingportion 316 of FIG. 3. Rotating portion 706 may rotate between openposition 334 and closed position 336. Cam actuator 720 may connect torotating portion of cam latch 702 and may cause rotating portion 706 torotate.

Cam 712 may include slot 710 and collar 714. Collar 714 may includenotch 716. Securing portion 718 of cam 712 may secure secured portion704 of cam latch 702 when rotating portion 706 is in closed position336. Each slot 710 of cam 712 may receive secured portion 704 asrotating portion 706 may transition from open position 334 to closedposition 336.

Lock 722 may include: arm 724, spring 726, and retraction device 728.Retraction device 728 may be a solenoid. Lock 722 arm 724 may engagenotch 716 in collar 714. Spring 726 may bias arm 724 to engage notch 716when cam 712 and connected collar 714 may be rotated to align with arm724. Retraction device 728 may be used to extract arm 724 from notch 716against any force exerted upon arm 724 by spring 726.

With reference now to FIGS. 8A-8B, FIGS. 8A-8B are a diagram of afolding wing including a latch assembly in accordance with anillustrative embodiment; FIG. 8A, is a diagram of the folding wing in aflight position with the latch assembly in a closed position inaccordance with an illustrative embodiment; FIG. 8B is a diagram of thefolding wing in a folded position, with the latch assembly in an openposition in accordance with an illustrative embodiment.

More specifically, latch assembly 802 for a wing, such as wing 300 ofFIG. 3, may include latch actuator 804, and rotating portion 806. Wing300 may include unfixed portion 808 and fixed portion 810. Unfixedportion 808 may be connected to fixed portion 810 near a top side ofeach respective portion and rotate about fold axis 812. Latch assembly802 may be in closed position closed position 336 shown in FIG. 8A.Closed position 336 of latch assembly 802 may secure secured portion 814of unfixed portion 808 with securing portion 820, as shown in FIG. 8B,of rotating portion 806 of fixed portion 810. Rotating portion 806 maybe mounted on a fixed portion lower-side stop 816.

Wing 300 may have fold actuator 818 located within fixed portion 810 andconfigured to rotate unfixed portion 808 about fold axis 812. Unfixedportion 808 may be rotated upward when rotating portion 806 is not inclosed position 336. FIG. 8B shows rotating portion 806 rotated to openposition 334. Rotating portion 806 may be rotated to open position 334by retraction of latch actuator 804.

As may be shown in further detail in following figures, rotating portion806, secured portion 814, and securing portion 820 may be configured invarious manners. Latch assembly 802 may be configured as a barrel latch,as a hook latch, as a bear claw latch, or as a cam latch.

With reference to FIG. 9 through FIG. 11, FIG. 9 through FIG. 11 arediagrams of a wing with a latch assembly configured as a barrel latch isdepicted in accordance with an illustrative embodiment. FIG. 9 is adiagram of a wing with a barrel latch, the wing almost in a flightposition, the barrel latch in the open position, and a lock of thebarrel latch in a disengaged position, in accordance with anillustrative embodiment. FIG. 10 is a diagram of a wing with a barrellatch, the wing in a flight position, the barrel latch in the openposition, and a lock of the barrel latch in a disengaged position, inaccordance with an illustrative embodiment. FIG. 11 is a diagram of awing with a barrel latch, the wing in a flight position, the barrellatch in a closed position, and a lock of the barrel latch in an engagedposition, in accordance with an illustrative embodiment.

With reference to FIG. 9, FIG. 9 is a diagram of a wing with a barrellatch, the wing almost in a flight position, the barrel latch in theopen position, and a lock of the barrel latch in a disengaged position,in accordance with an illustrative embodiment.

More specifically, FIG. 9 shows a perspective view diagram of a latchassembly connected to a fixed portion of a wing, where barrel latch 902may be an example of an embodiment of latch assembly 322 of FIG. 3. Forbetter viewing of barrel latch 902, unfixed portion 310 of wing 300, asshown in FIG. 3, is cut away and not shown in the foreground of FIG. 9.However, secured portion 906, which may be connected to unfixed portion310, is shown engaged with rotating portion 908. Lock 910 is shownengaged with rotating portion 908. Also shown is fold actuator 940,which may connect to unfixed portion 310.

Unfixed portion 310 of FIG. 3 (cutaway and not shown in FIG. 9) mayconnect to fixed portion 904 at fold axis 938. Fold actuator 940 maymove unfixed portion 310 between flight position 302 and folded position304 by rotating unfixed portion 310 about fold axis 938.

Barrel latch 902 may include secured portion 906, rotating portion 908,lock 910, and barrel actuator 922 (portions of barrel actuator 922 thatare located within fixed portion 904 are not shown in FIG. 9, to enhancevisual clarity of FIG. 9). Rotating portion 908 may include barrel 912.Barrel 912 may include slot 914, securing portion 916, notch 918, andbarrel lug 920. Barrel 912 may be cylindrically shaped. Rotating portion908 may be an embodiment of rotating portion 316 of FIG. 3.

Secured portion 906 may include T-shaped end 926. In FIG. 9, T-shapedend 926 is shown cut away from unfixed portion 310. Secured portion 906may be an example of an embodiment of secured portion 320 of FIG. 3.Secured portion 906 may be attached to a second portion, such as secondportion 318 of wing 300 of FIG. 3.

Lock 910 may include rod lug 928, rod 930, and arm 932. Arm 932 mayinclude target 934. Target 934 may be sensed by target/position sensor936. Target 934 may be on every arm 932 or on less than every arm 932,of barrel latch 902. Sensor 936 may sense proximity of target 934 andmay indicate that lock 910 may be in engaged position 330 of FIG. 3.Sensor 936 may be mounted on fixed portion 904, and may be mounted on aforward side or on an aft side of barrel 912 so as to be able to sensetarget 934 mounted on arm 932. Limiting target 934 and sensor 936 tobeing on less than every arm 932 may reduce an overall weight of barrellatch 902.

Barrel latch 902 may prevent rotation an unfixed portion 310 and awingtip, such as unfixed portion 120, unfixed portion 122, unfixedportion 310, and wingtip 312, of FIGS. 1, 2, and 3; of a wing, such aswing 102, wing 104, and wing 300 of FIGS. 1, 2, and 3.

Lock 910 may engage rotating portion 908 of barrel latch 902 whenrotating portion 908 may be in closed position 336. Lock 910 may preventrotation of rotating portion 908 of barrel latch 902 when lock 910 isengaged with notch 918 in barrel 912.

Barrel 912 may be rotated by motion of barrel actuator 922. Barrelactuator 922 may connect to barrel lug 920. Barrel lug 920 may be anextension of barrel 912. In the example shown in FIG. 9, extending thebarrel actuator 922 may rotate barrel 912 in the direction shown byarrow 924. In the example shown in FIG. 9, barrel actuator 922 may befully extended, and further rotation of barrel 912 in a directionindicated by arrow 924 may be impeded by T-shaped end 926 of securedportion 906. Retracting barrel actuator 922 may rotate barrel 912opposite the direction indicated by arrow 924.

Rotating portion 908 may rotate between open position 334 and closedposition 336. Securing portion 916 of rotating portion 908 may securesecured portion 906 of barrel latch 902 when rotating portion 908 is inclosed position 336. Slot 914 of rotating portion 908 may receivesecured portion 906 when rotating portion 908 may be in closed position336. Amount of barrel rotation, and/or position of barrel may be sensedby sensor 936.

T-shaped end 926 may be received by slot 914 of rotating portion 908when rotating portion 908 is in open position 334. T-shaped end 926 ofsecured portion 906 may be secured by securing portion 916 of rotatingportion 908 when rotating portion 908 may be in closed position 336.

With reference to FIG. 10, FIG. 10 is a diagram of a wing with a barrellatch, the wing not in a flight position, and the barrel latch in anopen position, in accordance with an illustrative embodiment. Morespecifically, FIG. 10 shows a perspective zoomed-in view on one half ofbarrel latch 1002, marked as view 10-10 in FIG. 9. Fixed portion 1042 isshown not in contact with unfixed portion 1040, as may be the case justbefore reaching or just after leaving flight position.

For clarity of viewing barrel latch 1002, only a cutaway part of a lowerside of unfixed portion 1040, and only a cutaway part of a lower side offixed portion 1042 are shown in FIGS. 10-12. Because the perspectiveview and numbered components remain the same in FIGS. 10-12, but somecomponent positions may change, item numbers in FIG. 10 are carried onthrough FIG. 11 and FIG. 12.

In FIG. 10, barrel latch 1002 is shown in open position 334 with lock1004 in disengaged position 332. Lock 1004 may be in disengaged position332 when arm 1006 may not be engaged in notch 1008.

Similar to FIG. 9, barrel latch 1002 may include: rotating portion 1010,secured portion 1012, and lock 1004. Rotating portion 1010 may include:barrel 1014, barrel lug 1016, barrel actuator 1018, and outer lug 1020.Barrel may include slot 1022, securing portion 1024, and notch 1008.Secured portion 1012 may include T-shaped end 1026, and inner lug 1028.Lock 1004 may include: lock actuator 1030, rod lug 1032, rod 1034, arm1006, and target 1036.

Barrel lug 1016 may extend from barrel 1014. Barrel lug 1016 may beconnected to barrel actuator 1018. Outer lug 1020 may be connected tofixed portion 306 of wing 300 of FIG. 3. Inner lug 1028 may be connectedto unfixed portion 310 of wing 300 of FIG. 3.

Lock 1004 may be in disengaged position 332 when barrel actuator 1018may extend and rod 1034 may be rotated in direction indicated by arrow1038. Rod 1034 may lift arm 1006 up away from barrel 1014. With arm 1006up away from barrel 1014, arm 1006 may not be engaged with notch 1008.

When arm 1006 may be disengaged from notch 1008, barrel actuator 1018may retract and rotate barrel 1014 in direction indicated by arrow 1038.Barrel 1014 rotating in direction indicated by arrow 1038, may rotatenotch 1008 back away from arm 1006 to position of arm 1006 as shown inFIG. 10.

Because secured portion 1012 may be connected to unfixed portion 1040,when barrel latch 1002 is in position shown in FIG. 10, with securingportion 1024 of rotating portion 1010 rotated away from secured portion1012, and slot 1022 positioned so that secured portion 1012 may bewithdrawn from barrel 1014, then secured portion 1012 may be withdrawnfrom barrel 1014 as unfixed portion 1040 is rotated away from fixedportion 1042, and wing 300 moves toward folded position 304.

Also shown is target/position sensor 1044. Sensor 1044 may sense aposition and/or an amount of rotation of barrel 1014. Sensor 1044 maysense the position and/or the amount rotation of barrel 1014 viamechanical, electrical, optical, sonic, magnetic, other appropriatemeans, or any combination thereof. Sensor 1044 may be located at anypoint along barrel 1014, and more than one sensor 1044 may be used.Sensor 1044 may be mounted on unfixed portion 310 of wing 300.

One target/position sensor 1044 is omitted in FIG. 10 to allow betterviewing of notch 1008. As mentioned above, each arm 1006 may have target1036, and each target 1036 may have sensor 1044 connected to fixedportion 306. Sensor 1044 may sense the position of target 1036 on arm1006 via mechanical, electrical, optical, sonic, magnetic, otherappropriate means, or any combination thereof.

With reference to FIG. 11, FIG. 11 is a diagram of a wing with a barrellatch, the wing in a flight position, the barrel latch in the openposition, and a lock of the barrel latch in a disengaged position, inaccordance with an illustrative embodiment. More specifically FIG. 11 isa perspective zoomed-in view on one half of barrel latch 1002, marked asview 10-10 in FIG. 9.

In FIG. 11, barrel latch 1002 is shown in open position 334 with lock1004 in disengaged position 332. Lock 1004 may be in disengaged position332 when arm 1006 may not be engaged in notch 1008. FIG. 11 differs fromFIG. 10 by showing T-shaped end 1026 engaged in slot 1022 of barrel 1014before rotating portion 1010 has rotated securing portion 1024 to secureT-shaped end 1026 within barrel 1014.

Because secured portion 1012 may be connected to unfixed portion 1040,when barrel latch 1002 is in position shown in FIG. 11, with securingportion 1024 of rotating portion 1010 rotated away from secured portion1012, and slot 1022 positioned so that secured portion 1012 may bewithdrawn from barrel 1014, then secured portion 1012 may be withdrawnfrom barrel 1014 (as shown in FIG. 10) as unfixed portion 1040 isrotated away from fixed portion 1042, and wing 300 moves toward foldedposition 304.

One target/position sensor 1044 is omitted in FIG. 11 to allow betterviewing of notch 1008. As mentioned above, each arm 1006 may have target1036, and each target 1036 may have sensor 1044 connected to fixedportion 306. Sensor 1044 may sense the position of target 1036 on arm1006 via mechanical, electrical, optical, sonic, magnetic, otherappropriate means, or any combination thereof.

With reference to FIG. 12, FIG. 12 is a diagram of a wing with a barrellatch, the wing in a flight position, the barrel latch in a closedposition, and a lock of the barrel latch in an engaged position, inaccordance with an illustrative embodiment. The numbering for items inFIG. 10 is retained and carried on through FIG. 12. More specifically,secured portion 1012 is shown engaged by securing portion 1024 of barrel1014, and arm 1006 is shown engaged with notch 1008.

Among the ways that FIG. 12 differs from FIG. 10, is that when barrellatch 1002 is in closed position 336 with lock 1004 in engaged position330, as shown in FIG. 12, unfixed portion 1040 may be secured against,and cannot be rotated away from, fixed portion 1042. With barrel latch1002 configured as shown in FIG. 12, wing 300 may be secured in flightposition 302 and fold actuator 818 of FIG. 8, may not push unfixedportion 310 up to folded position 304.

With lock 1004 in engaged position 330 as shown in FIG. 12, lockactuator 1030 may be retracted. Retraction of lock actuator may pull rodlug 1032 back toward fixed portion 306 and rotate rod 1034 in directionindicated by arrow 1038. Rotation of rod 1034 in direction indicated byarrow 1038 may rotate arm 1006 down to engage in notch 1008 when barrel1014 may be rotated to closed position 336 as it is shown FIG. 12.

In FIG. 12, inner lug 1028 can be seen nested inside of outer lug 1020.Inner lug 1028 nesting in outer lug 1020 may transfer torsion betweensecured portion 1012 and rotating portion 1010.

Inner lug 1028 nesting in outer lug 1020 may assist transmission atorsional load, as well as a forward and an aft shear load, securedportion 1012 and rotating portion 1010, and may reduce an amount oftorsion and an amount of stress between T-shaped end 1026 and securingportion 1024.

With reference to FIGS. 13 through 17, FIG. 13 is a diagram of aperspective view from above looking aft inside a cutaway of a wing witha hook latch, the wing in a flight position, and the hook latch in aclosed position, in accordance with an illustrative embodiment. FIG. 14is a diagram of a perspective view from above looking aft inside acutaway of a wing with a hook latch, zoomed in on one-half of FIG. 13,the wing not in a flight position, and the hook latch in an openposition, in accordance with an illustrative embodiment. FIG. 15 is adiagram of a perspective view from above looking aft inside a cutaway ofa wing with a hook latch, zoomed in on one-half of FIG. 13, the wing ina flight position, and the hook latch in an open position, in accordancewith an illustrative embodiment. FIGS. 14-16 retain the perspective andsame elements at FIG. 13, but some elements may be shown in changedpositions, thus the item numbers in FIG. 14 are carried over in FIG. 15and FIG. 16. FIG. 16 is a diagram of a perspective view from abovelooking aft inside a cutaway of a wing with a hook latch, zoomed in onone-half of FIG. 13, the wing in a flight position, and the hook latchin a closed position, in accordance with an illustrative embodiment.

FIGS. 17A-17B are a diagram of a side view of a hook latch, inaccordance with an illustrative embodiment; FIG. 17A is a diagram of aside view of a hook latch in transition between an open position and aclosed position, with a lock of the hook latch in a disengaged position,in accordance with an illustrative embodiment; and FIG. 17B is a diagramof a side view of a hook latch in the closed position, with a lock ofthe hook latch in an engaged position, in accordance with anillustrative embodiment.

With reference to FIG. 13, FIG. 13 is a diagram of a perspective viewfrom above looking aft inside a cutaway of a wing with a hook latch, thewing in a flight position, and the hook latch in a closed position, inaccordance with an illustrative embodiment. More specifically, hooklatch 1302 may be an embodiment of latch assembly 322 of FIG. 3. Toenable clearer visualization of hook latch components, lock 326 aspresented in FIG. 3, is not presented in FIG. 13.

Hook latch 1302 may include rotating portion 1304, secured portion 1306,latch bar 1308, latch actuator 1310, rotation bar 1312, lug 1314,unfixed portion lower-side stop 1316, unfixed portion 1318, fixedportion 1320, and fixed portion lower-side stop 1322. Fixed portion 1320may be comprised by first portion 314 of FIG. 3.

Unfixed portion 1318 may be comprised by second portion 318 of FIG. 3;of a wing, such as wing 102, wing 104, and wing 300 of FIGS. 1, 2, and3; and of an aircraft, such as aircraft 100 of FIGS. 1 and 2. Hook latch1302 may prevent rotation of unfixed portion 1318.

Rotating portion 1304 may be an embodiment of rotating portion 316 ofFIG. 3. Rotating portion 1304 may rotate between open position 334 andclosed position 336. Rotating portion 1304 may be attached to rotationbar 1312. Rotation bar 1312 may include a lug 1314. Lug 1314 may connectto latch actuator 1310. Thus, latch actuator 1310 may move lug 1314 andmove any rotating portion 1304 connected to rotation bar 1312.

Rotation bar 1312 may be rotated by latch actuator 1310 and may engagerotating portion 1304 with latch bar 1308 of secured portion 1306.Rotation bar 1312 may be used to rotate a group of one or more rotatingportion 1304 in embodiments that may use more than one rotating portion1304, as shown in FIG. 12.

Secured portion 1306 may include latch bar 1308. Latch bar may besecured in unfixed portion lower-side stop 1316 of secured portion 1306.Secured portion 1306 may be an embodiment of secured portion 320 of FIG.3. Secured portion 1306 may be attached to unfixed portion 1318, whichmay be second portion 318 of FIG. 3.

With reference now to FIG. 14, FIG. 14 is a diagram of a perspectiveview from above looking aft inside a cutaway of a wing with a hooklatch, zoomed in on one-half of FIG. 13, the wing not in a flightposition, and the hook latch in an open position, in accordance with anillustrative embodiment. More specifically, FIG. 14 presents view 14-14of hook latch 1302 as marked in FIG. 13, with unfixed portion lower-sidestop 1316, and fixed portion lower-side stop 1322 cutaway, and twosignificant changes from the view presented in FIG. 13. View 14-14 ofFIG. 13 is changed in FIG. 14 by unfixed portion 1418 being shown movedout of flight position 302 and away from fixed portion 1420 after hooklatch 1402 was moved to open position 334, from the closed position 336,of FIG. 3, as shown in FIG. 13. Additionally, to enable clearervisualization of hook latch components, lock 326 as presented in FIG. 3,is not presented in FIG. 14.

Hook latch 1402 may include: unfixed portion lower-side stop 1404, fixedportion lower-side stop 1406, latch bar 1408, latch actuator 1410,rotation bar 1412, lug 1414, hook 1416, unfixed portion 1418, fixedportion 1420, securing portion 1422, of rotating portion 1424, rotationaxis 1426, and secured portion 1428.

Rotating portion 1424 may include securing portion 1422, which mayinclude hook 1416. As shown in FIG. 14, hook 1416 may disengage fromlatch bar 1408 when latch actuator 1410 is in an extended position. Whenlatch actuator 1410 is in a retracted position, lug 1414 may be movedtoward fixed portion 1420, and rotation bar 1412 may be rotated to theposition shown. Rotation bar 1412 in position shown in FIG. 14 may beopen position 334. In open position 334, each rotating portion 1424 mayretract each hook 1416 fully from any engagement with latch bar 1408such that secured portion 1428 may be moved away from rotating portion1424, and unfixed portion lower-side stop 1404 may move away fromcontact with fixed portion lower-side stop 1406. When unfixed portionlower-side stop 1404 is not in contact with fixed portion lower-sidestop 1406, wing 300 may not be in flight position 302, and aircraft maynot be ready for flight.

Securing portion 1422 may be an embodiment of securing portion 328 ofFIG. 3. Each additional securing portion 1422 that may be connected torotation bar 1412, may increase redundancy for any single securingportion 1422 connected to rotation bar 1412. Optimizing the strength ofeach securing portion 1422 connected to rotation bar 1412 against aselection of a quantity of securing portion 1422, may allow wing 300 tohave a folding capability and remain secured in flight position 302throughout a flight, with fewer components and/or at a lower weight thancurrently existing wing fold systems and latch assemblies.

With reference now to FIG. 15, FIG. 15 is a diagram of a perspectiveview from above looking aft inside a cutaway of a wing with a hooklatch, zoomed in on one-half of FIG. 13, the wing in a flight position,and the hook latch in an open position, in accordance with anillustrative embodiment. More specifically, FIG. 15 shows hook latch1402 as presented in FIG. 14, except hook latch 1402 is shown with wing300 in flight position 302. Therefore, items in FIG. 15 carry the samenumbers as presented in FIG. 14. To enable clearer visualization of hooklatch 1402 components, lock 326 as presented in FIG. 3, is not presentedin FIG. 15.

FIG. 15 shows that hook latch 1402 may also include slot 1502. Slot 1502may be comprised by rotating portion 1424.

FIG. 15 differs from FIG. 13 in that latch actuator 1410 is shownretracted. With latch actuator 1410 retracted, lug 1414 may be pulledback away from unfixed portion 1418, and rotation bar 1412 may move upand away from secured portion 1428, and may rotate about rotation axis1426, until reaching open position 334, as shown in FIG. 15. Whenrotation bar 1412 rotates away from secured portion 1428, slot 1502 maymove up and away from latch bar 1408. When latch bar 1408 is no longerencompassed within slot 1502, securing portion 1422 and hook 1416 may nolonger secure rotating portion 1424 to secured portion 1428.

When rotating portion 1424 is up and away from secured portion 1428,hook latch 1402 may be in open position 334, and unfixed portion 1418may be moved away from fixed portion 1420 by fold actuator 340, out offlight position 302 to folded position 304 of FIG. 3.

Latch bar 1408 may be received by slot 1502 of rotating portion 1424when rotating portion 1424 transitions between open position 334 andclosed position 336. Latch bar 1408 of secured portion 1428 may besecured by securing portion 1422 of rotating portion 1424 when rotatingportion 1424 is in closed position 336, as previously shown in FIG. 13.

Securing portion 1422 may secure latch bar 1408 of secured portion 1428of hook latch 1402 when rotating portion 1424 is in closed position 336.Slot 1502 of rotating portion 1424 may receive secured portion 1428 whenrotating portion 1424 may transition between open position 334 andclosed position 336.

With reference now to FIG. 16, FIG. 16 is a diagram of a perspectiveview from above looking aft inside a cutaway of a wing with a hooklatch, zoomed in on one-half of FIG. 13, the wing in a flight position,and the hook latch in a closed position, in accordance with anillustrative embodiment. More specifically, FIG. 16 presents view 14-14of hook latch 1302 as marked in FIG. 13, with unfixed portion lower-sidestop 1404, and fixed portion lower-side stop 1406 cutaway. To enableclearer visualization of hook latch components, lock 326 as presented inFIG. 3, is not presented in FIG. 16. Additionally, FIG. 16 retains theperspective and same elements at FIG. 14, but some elements may be inchanged positions, thus the item numbers in FIG. 14 are carried over inFIG. 16.

As shown in FIG. 14, hook 1416 may engage latch bar 1408 when latchactuator 1410 is in an extended position. When latch actuator 1410 is inthe extended position, lug 1414 may be moved fully toward unfixedportion 1418, and rotation bar 1412 may be rotated to the positionshown. Rotation bar 1412, in position shown in FIG. 14 may be closedposition 336. In closed position 336, each rotating portion may havehook 1416 fully engaged with latch bar 1408 such that secured portion1428 may not be moved away from rotating portion 1424, and unfixedportion lower-side stop 1404 may remain in contact with fixed portionlower-side stop 1406. When unfixed portion lower-side stop 1404 remainsin contact with fixed portion lower-side stop 1406, wing 300 may be inflight position 302, and aircraft may be ready for flight.

Securing portion 1422 may be an embodiment of securing portion 328 ofFIG. 3. Each additional securing portion 1422 that may be connected torotation bar 1412, may increase redundancy for any single securingportion 1422 connected to rotation bar 1412. Optimizing the strength ofeach securing portion 1422 connected to rotation bar 1412 against aselection of a quantity of securing portion 1422, may allow wing 300 tohave a folding capability and remain secured in flight position 302throughout a flight, with fewer components and/or at a lower weight thancurrently existing wing fold systems and latch assemblies.

With reference now to FIG. 17, FIG. 17 is a diagram of a side view of ahook latch, in accordance with an illustrative embodiment; FIG. 17A is adiagram of a side view of a hook latch in transition between an openposition and a closed position, with a lock of the hook latch in adisengaged position, in accordance with an illustrative embodiment; andFIG. 17B is a diagram of a side view of a hook latch in the closedposition, with a lock of the hook latch in an engaged position, inaccordance with an illustrative embodiment. More specifically, of hooklatch 1702 is shown without latch actuator 1310/1410, lug 1314/1414,fixed portion 1320/1420, and unfixed portion lower-side stop 1316 (asshown in FIG. 13 and FIG. 14) to enable viewing clarity of lock 1704 andlock/latch sensor 1706.

Hook latch 1702 may include: lock 1704, sensor 1706, and rotatingportion 1708. Lock 1704 may include lock actuator 1710 and pawl 1712.Pawl 1712 may include an extension, pawl lug 1714, and latch rotationaxis 1716. Rotating portion 1708 may include target 1718.

When, as in FIG. 17A, lock actuator 1710 may be in an extended position,pawl lug 1714 may be pushed to the right such that pawl 1712 may rotatein a direction indicated by arrow 1720 about latch rotation axis 1716,and pawl 1712 may rise so as to not make contact with rotating portion1708. Lock 1704 may be in disengaged position 332, as shown in FIG. 3,when pawl 1712 is not in contact with rotating portion 1708.

In FIG. 17A, rotating portion 1708 is not in open position 334 becausehook 1724 has not raised enough to allow latch bar 1726 to move awayfrom fixed portion lower-side stop 1728. In open position 334, rotatingportion 1708 may be rotated up and toward fixed portion 306 enough sothat hook 1724 may be above latch bar 1726 sufficiently to allow foldactuator 340 to move unfixed portion 1722 away from fixed portionwithout latch bar 1726 contacting hook 1724 or any part of rotatingportion 1708.

Sensor 1706 may be mounted on unfixed portion 1722. In the positionshown in FIG. 17A, sensor 1706 may sense that target 1718 on rotatingportion 1708 is not in a position that corresponds to closed position336 for hook latch 1702. Sensor 1706 may indicate a status that hooklatch 1702 may be not in closed position 336 when target 1718 is notproperly aligned with sensor 1706. Wing 300 may be considered not readyfor flight when hook latch 1302 may be not in closed position 336.

Sensor 1706 may sense target 1718 mechanically, electronically,ultrasonically, optically, by other appropriate means, or by anycombination thereof. When sensor 1706 senses target 1718 vianon-mechanical means, reliability may be increased, and weight of sensor1706 and hook latch 1702 may be reduced compared to current mechanicalsensing devices.

In the position shown in FIG. 17B, sensor 1706 may sense that target1718 on rotating portion 1708 is in a position that corresponds to hooklatch 1702 in closed position 336. If rotating portion 1708 is in theposition shown in FIG. 17B, but unfixed portion 1722 were not in theposition shown in FIG. 17B, then sensor 1706 may not be aligned withtarget 1718, and sensor 1706 may not sense that hook latch 1702 is inclosed position 336.

When rotating portion 1708 is in closed position 336, pawl 1712 maytransition between engaged position 330, shown in FIG. 17B, anddisengaged position 332, shown in FIG. 17A. Engaged position 330 mayprevent rotating portion 1708 from moving out of closed position 336.Pawl 1712 may be moved to engaged position 330 by a retraction of lockactuator 1710 pulling pawl lug 1714 left towards fixed portion 306 tothe position shown in FIG. 17B.

With reference to FIG. 18 through 21, the figures diagram a wing with abear claw latch in positions from an open position to a closed position.FIG. 18 is a diagram of a wing with a bear claw latch, the wing almostin a flight position, the bear claw latch in the open position, and alock of the bear claw latch in a disengaged position, in accordance withan illustrative embodiment; FIG. 19 is a diagram of a wing with a bearclaw latch, the wing in a flight position, the bear claw latch in theopen position, and a lock of the bear claw latch in the disengagedposition, in accordance with an illustrative embodiment; FIG. 20 is adiagram of a wing with a bear claw latch, the wing in a flight position,the bear claw latch in the closed position, and a lock of the bear clawlatch in the disengaged position, in accordance with an illustrativeembodiment; FIG. 21 is a diagram of a wing with a bear claw latch, thewing in a flight position, the bear claw latch in the closed position,and a lock of the bear claw latch in an engaged position, in accordancewith an illustrative embodiment. Because the perspective and componentsremain the same, although some components may be in different positions,item numbering in FIG. 18 remains the same through FIGS. 19-21.

With reference to FIG. 18, FIG. 18 is a diagram of a wing with a bearclaw latch, the wing almost in a flight position, the bear claw latch inan open position, and a lock of the bear claw latch in a disengagedposition, in accordance with an illustrative embodiment. Bear claw latch1802 may be an example of an embodiment of latch assembly 322 of FIG. 3.

Bear claw latch 1802 may include: secured portion 1804, group ofopenings 1806, nub gap 1808, alignment gaps 1810, group of hooks 1812,securing portion 1814, rotating portion 1816, torsion nub 1818, base1820, rotation bar 1822, slot 1824, aft claw actuator 1826, link 1828,forward claw actuator 1830, lug 1832, retraction device 1834, spring1836, lock 1838, and gap lugs 1840. Bear claw latch 1802 may preventrotation of second portion 1844. Second portion 1844 may be an exampleof an embodiment of second portion 318 of FIG. 3; of a wing, such aswing 102, wing 104, and wing 300 of FIGS. 1, 2, and 3; and of anaircraft, such as aircraft 100 of FIGS. 1 and 2, with respect to firstportion 1846, such as first portion 314 of FIG. 3.

Secured portion 1804 may include group of openings 1806, nub gap 1808,and alignment gaps 1810. Secured portion 1804 may be an example of anembodiment of secured portion 320 of FIG. 3. Secured portion 1804 may beconnected to second portion 1844. Second portion 1844 may be an exampleof an embodiment of unfixed portion 310 of wing 300 of FIG. 3.

Secured portion 1804 may be secured by group of hooks 1812 of securingportion 1814 of rotating portion 1816 when bear claw latch 1802 is in aclosed position, such as closed position 336 in FIG. 3. Group ofopenings 1806 may receive group of hooks 1812 of securing portion 1814of rotating portion 1816 when rotating portion 1816 transitions betweenopen position 334 and closed position 336.

Nub gap 1808 may engage torsion nub 1818. Engagement of torsion nub 1818with nub gap 1808 may transfer torsion between secured portion 1804 andbase 1820 of rotating portion 1816.

Torsion nub 1818 may also help align group of openings 1806 with groupof hooks 1812. Torsion nub 1818 may assist transmission a torsionalload, as well as a forward and an aft shear load, between securedportion 1804 of bear claw latch 1802 affixed to second portion 1844 andbase 1820 of rotating portion 1816 of bear claw latch 1802 affixed tofirst portion 1846. First portion 1846 may be an embodiment of fixedportion 306 of FIG. 3. Torsion nub 1818 may reduce an amount of torsionand an amount of stress between group of openings 1806 and group ofhooks 1812.

Rotating portion 1816 may be an embodiment of rotating portion 316 ofFIG. 3. Rotating portion 1816 may include group of hooks 1812, securingportion 1814, torsion nub 1818, base 1820, rotation bar 1822, slot 1824,aft claw actuator 1826, link 1828, forward claw actuator 1830, lug 1832,retraction device 1834, spring 1836, lock 1838, and gap lugs 1840.

Rotating portion 1816 may rotate between open position 334 as shown inFIG. 18, and closed position 336 as shown in FIG. 18. Rotating portion1816 may be rotated about rotation bar 1822 by its respective clawactuator. Rotating portion 1816 may engage group of hooks 1812 ofsecuring portion 1814 with group of openings 1806 of secured portion1804.

Lug 1832 on securing portion 1814 may connect to aft claw actuator 1826via link 1828. Aft claw actuator 1826 may be attached to aft spar 1833of wing box 308. Aft claw actuator 1826 may be attached to aft spar 1833of wing box 308 in an aft trunnion mounting. A rotation axis of the afttrunnion mounting for the aft claw actuator may be substantiallyvertical. Thus, a central axis of aft claw actuator may not be directlyaligned with an axis of motion for lug 1832 on securing portion 1814.

Forward claw actuator 1830 may be connected to rib 1842. Forward clawactuator 1830 may be mounted in a forward trunnion. A rotation axis forthe forward trunnion may be substantially horizontal. Rib 1842 may forman outside edge of wing box 308. Rib 1842 may be reinforce to supportforward claw actuator 1830 or forces generated by forward claw actuator1830. Forward claw actuator 1830 may connect directly to lug 1832. Acentral axis of forward claw actuator 1830 may be directly aligned withan axis of motion for lug 1832 on securing portion 1814 of rotatingportion 1816.

Each claw actuator may be powered hydraulically, electrically, by otherappropriate methods, or by any combination thereof. Each claw actuatormay have a different power source from another claw actuator.

Group of hooks 1812 may be formed as a single piece. Group of hooks 1812may include a greater or lesser number of hooks than are represented inFIG. 181 through FIG. 18. Group of openings 1806 may have a number ofopenings that are at least equal to a number of hooks in group of hooks1812.

Securing portion 1814 may be an embodiment of securing portion 328 ofFIG. 3. Securing portion 1814 may secure secured portion 1804 of bearclaw latch 1802 when rotating portion 1816 is in closed position 336.

Locks 1838 may include a linear retraction device that, when rotatingportion 1816 is in a closed position, may transition locks 1838 betweenan engaged position and a disengaged position. The engaged position mayprevent rotating portion 1816 from leaving the closed position.

With reference now to FIG. 19, FIG. 19 is a diagram of a wing with abear claw latch, the wing in a flight position, the bear claw latch inthe open position, and a lock of the bear claw latch in the disengagedposition, in accordance with an illustrative embodiment. Second portion1844 and first portion 1846 may be closer together in FIG. 19 than theywere in FIG. 18.

When wing 300 is in flight position 302, torsion nub 1818 may engagewith nub gap 1808. Gap lugs 1840 may align and engage with alignmentgaps 1810. When gap lugs 1840 align and engage with alignment gaps 1810,then rotating portion 1816 may be rotated by claw actuators to engagewith secured portion 1804 on second portion 1844.

Rotating portion 1816 may receive secured portion 1804 into slot 1824when rotating portion 1816 transitions from open position 334 to closedposition 336. Securing portion 1814 may include group of hooks 1812.Group of hooks 1812 may engage group of openings 1806 in secured portion1804 as securing portion 1814 moves from open position 334 to closedposition 336. In FIG. 18, where securing portion 1814 has not fullymoved to closed position 336, secured portion 1804 may not be fullyengaged with slot 1824, and group of hooks 1812, may not be fullyinserted into group of openings 1806.

Lock 1838 is shown in disengaged position 332. Lock may be considered indisengaged position 332 because lock 1838 may not be positioned betweenlug 1832 and rib 1842. Lock 1838 may have spring 1836 disposed to pushlock 1838 into engaged position 330. Lock 1838 may have retractiondevice 1834 energized to counteract push of spring 1836 and hold lock1838 retracted from a position between lug 1832 and rib 1842.

Referring now to FIG. 20, FIG. 20 is a diagram of a wing with a bearclaw latch, the wing in a flight position, the bear claw latch in theclosed position, and a lock of the bear claw latch in the disengagedposition, in accordance with an illustrative embodiment. In closedposition 336, secured portion 1804 may be fully engaged with slot 1824,and group of hooks 1812, may be fully inserted into group of openings1806.

As shown in FIG. 20, wing 300 is in flight position 302, and bear clawlatch 1802 is in flight position 302 with wingtip 312 fully extendedwith wingspan 132 as shown for aircraft 100 in FIG. 1. As shown in FIG.20, wing 300 should be capable of sustaining flight loads, and wing 300ready for flight. Lock 1838 may provide a redundant feature to preventbear claw latch 1802 from moving out of closed position 336.

Referring now to FIG. 21, FIG. 21 is a diagram of a wing with a bearclaw latch, the wing in a flight position, the bear claw latch in theclosed position, and a lock of the bear claw latch in an engagedposition, in accordance with an illustrative embodiment. With lock 1838in engaged position 330, spring 1836 may extend and push lock 1838 inbetween lug 1832 and rib 1842.

Spring 1836 provides a mechanism that may hold lock 1838 in engagedposition 330 as long as retraction device 1834 is not powered andactivated to retract lock 1838.

Neither claw actuator may have enough force to overcome a blockingeffect of a first side of lock 1838 contacting lug 1832 and a secondside of lock 1838 contacting rib 1842.

Lock 1838 being in engaged position 330 may not allow either clawactuator to pull lug 1832 away from secured portion 1804. Retractiondevice 1834 may have to be energized, and overpower spring 1836, toretract lock 1838 from engaged position 330, before either claw actuatormay be activated to retract rotating portion 1816 from closed position336 to open position 334.

With reference now to FIGS. 22-25, FIGS. 22-25 are diagrams of aperspective upward looking view of a cam latch. FIG. 22 is a diagram ofa perspective upward looking view of a cam latch in an open position,and a lock of the cam latch in a disengaged position, in accordance withan illustrative embodiment; FIG. 23 is a perspective upward looking viewdiagram of a cam latch in an open position for a wing in a flightposition, and a lock of the cam latch in a disengaged position, inaccordance with an illustrative embodiment; FIG. 24 is a perspectiveupward looking view diagram a cam latch in a closed position for a wingin a flight position, and a lock of the cam latch in a disengagedposition, in accordance with an illustrative embodiment; and FIG. 25 isa perspective upward looking view diagram a cam latch in a closedposition for a wing in a flight position, and a lock of the cam latch inan engaged position, in accordance with an illustrative embodiment.Accordingly, because the perspective and components remain unchanged,although some component positions may change, item numbers marked inFIG. 22 will be carried through FIGS. 23-25.

With reference now to FIG. 22, FIG. 22 is a diagram of a perspectiveupward looking view of a cam latch in an open position, and a lock ofthe cam latch in a disengaged position, in accordance with anillustrative embodiment. More specifically, FIG. 22 cam latch 2202 isshown in open position 334, with wing 300 close to, but not in, flightposition 302, and cam latch 2202 configured to latch unfixed portion2204 to fixed portion 2206 of wing 300, as shown in FIG. 3.

Cam latch 2202 may include: secured portion 2208, rotating portion 2210,and lock 2212. Cam latch 2202 may be an embodiment of latch assembly 322of FIG. 3. Cam latch 2202 may prevent rotation of unfixed portion 2204about fold axis 2214.

Although FIG. 22 shows unfixed portion 2204 comprised of four similarsections, being received by one section of fixed portion 2206, it isunderstood that unfixed portion 2204 may comprise more or less than foursections, and that fixed portion 2206 may comprise a number of sectionsfrom one up to the number of sections of the unfixed portion 2204.Optimizing the strength of each section versus the number of sectionsused may allow the cam latch design to occupy less space, and use lessmaterial and/or weight than current latch designs for wing foldingsystems.

Secured portion 2208 may include group of openings 2216. Each opening ingroup of openings 2216 may be a semicircular shape. Secured portion 2208may be connected to unfixed portion 2204 of wing 300 of FIG. 3, whichmay be second portion 318 of FIG. 3; of a wing, such as wing 102, wing104, and wing 300 of FIGS. 1, 2, and 3, with respect to rotating portion2210. Rotating portion 2210 may include: cam 2218. Cam 2218 may includeslot 2220, securing portion 2222, notch 2224, and collar 2225. Rotatingportion 2210 may be an embodiment of rotating portion 316 of FIG. 3.Rotating portion 2210 may connect to fixed portion 2206, which may befirst portion 314 of FIG. 3; of a wing, such as wing 102, wing 104, andwing 300 of FIGS. 1, 2, and 3. Rotating portion 2210 may rotate betweenopen position 334 and closed position 336.

Cam 2218 may be a cylindrical shape with slot 2220 indentations. Thus,securing portion 2222 may be substantially a solid hemisphere of thecam. Cam may have a notch in collar 2225. Collar 2225 may be connectedonto, or integrally molded with cam 2218, such that cam 2218 and collar2225 may rotate together. Securing portion 2222 of cam 2218 may securesecured portion 2208 when rotating portion 2210 is in closed position336. Slot 2220 of cam 2218 may receive secured portion 2208 whenrotating portion 2210 is in open position 334.

Securing portion 2222 may have a circular circumference. A diameter ofthe semicircular shape of each opening in group of openings 2216 may besized to engage the circular circumference of securing portion 2222 ofcam 2218. Slot 2220 may be an indentation that may be a removal ofsubstantially a hemisphere, for a distance along a length of cam 2218,from the cylindrical shape of cam 2218.

Lock 2212 may include arm 2226, retraction device 2228, and spring 2230.Lock 2212 may be a size and a shape to engage notch 2224 in collar 2225of rotating portion 2210. Spring 2230 may connect to and bias arm 2226to contact rotating portion 2210 and to engage notch 2224. Retractiondevice 2228 may be enabled to retract spring 2230 and retract arm 2226out of notch 2224.

With reference now to FIG. 23, FIG. 23 is a perspective upward lookingview diagram of a cam latch in an open position for a wing in a flightposition, and a lock of the cam latch in a disengaged position, inaccordance with an illustrative embodiment. More specifically, FIG. 23shows unfixed portion 2204 after rotating about fold axis 2214 intofixed portion 2206 such that unfixed portion 2204 and fixed portion 2206may be aligned in flight position 302 of FIG. 3.

In order for secured portion 2208 to move from a position of securedportion 2208 as shown in FIG. 22 to a position of secured portion 2208as shown in FIG. 23, unfixed portion 2204, including secured portion2208, and fixed portion 2206, including rotating portion 2210 may besized so that a side of secured portion 2208 that is closest to fixedportion 2206, may be shorter, measured from fold axis 2214 than adistance from fold axis 2214 to a planar surface of slot 2220, when theplanar surface of slot 2220 is orthogonal to a line from a center offold axis 2214 to a center of cam 2218.

Thus, for a position shown for unfixed portion 2204 in FIG. 22 to moveto a position for unfixed portion 2204 as shown in FIG. 23, rotatingportion 2210 may need to be rotated such that each slot 2220 in cam 2218of rotating portion 2210 may be positioned to allow the side of securedportion 2208 that is closest to fixed portion 2206 to pass through eachslot 2220 such that cam 2218 centers over group of openings 2216.

Rotating portion 2210 may be rotated by a cam actuator (not shown). Thecam actuator may connect to cam 2218. The cam actuator may be an exampleof an embodiment of latch actuator 342 of FIG. 3.

Group of openings 2216 may be received by each slot 2220 of cam 2218when rotating portion 2210 is in open position 334. Group of openings2216 of secured portion 2208 may be secured by securing portion 2222 ofrotating portion 2210 when rotating portion 2210 is in closed position336, as in FIG. 3.

With reference to FIG. 24, FIG. 24 is a perspective upward looking viewdiagram a cam latch in a closed position for a wing in a flightposition, and a lock of the cam latch in a disengaged position, inaccordance with an illustrative embodiment. More specifically, cam latch2202 is shown with rotating portion 2210 in closed position 336 for wing300 in flight position 302, with arm 2226 of lock 2212 in disengagedposition 332, as shown in FIG. 3.

Lock 2212 may be in disengaged position 332 when arm 2226 is not engagedwith notch 2224. Cam 2218 may rotate when lock 2212 is in disengagedposition 332. With lock 2212 in disengaged position 332, cam actuatormay rotate cam 2218 180 degrees from a position of cam 2218 as shown inFIG. 24. If cam 2218 were rotated 180 degrees from the position of cam2218 as shown in FIG. 24, then unfixed portion 2204 could move away fromfixed portion 2206 to be in a position of unfixed portion 2204 as shownin FIG. 22.

However, even with lock disengaged, when rotating portion 2210 remainsin a position of rotating portion 2210 as shown in FIG. 24, securedportion 2208 and unfixed portion 2204 may be secured to rotating portion2210 and fixed portion 2206.

With reference to FIG. 25, FIG. 25 is a perspective upward looking viewdiagram a cam latch in a closed position for a wing in a flightposition, and a lock of the cam latch in an engaged position, inaccordance with an illustrative embodiment. More specifically, cam latch2202 is shown with rotating portion 2210 in closed position 336 for wing300 in flight position 302, with arm 2226 of lock 2212 in engagedposition 330.

Lock 2212 may include: arm 2226, retraction device 2228 and spring 2230.Arm 2226 may rotate about a pivot point. Spring 2230 may exert a forceon arm 2226 to move arm 2226 into notch 2224 when arm 2226 may alignwith notch 2224. Retraction device may energize to retract spring 2230,counteract the force of spring 2230 on arm 2226, and thus move arm 2226out of notch 2224.

Rotating portion 2210 may not rotate with lock 2212 in engaged position330. Lock 2212 may be in engaged position when arm 2226 engages notch2224. Secured portion 2208 may not move away from rotating portion 2210until retraction device 2228 may activate, counteract the force ofspring 2230 on arm 2226, and move arm 2226 to withdraw from notch 2224.

With reference to FIG. 26, FIG. 26 is a diagram of operations for amethod of folding and unfolding a wing, depicted in accordance with anillustrative embodiment; FIG. 26 shows operation 2602 through operation2620;

Method 2600 illustrated in FIG. 26 may be implemented in a wing, such aswing 102, wing 104, and wing 300 in FIGS. 1, 2, and 3.

Method 2600 may include operations listed below. Method 2600 may startwith operation 2602 and end after operation 2620. Operations listed formethod 2600 may be performed in an order other than that presented. Someoperations may be performed simultaneously. Some operations may beomitted. Operations other than those listed may be added. Performance ofsome operations, or ordering of operations, may be dependent upon abeginning state of the wing, such as a flight position or a foldedposition, or being in transition between states.

Method 2600 may include rotating an unfixed portion of a wing may withrespect to a fixed portion of the wing between a flight position of thewing and a folded position of the wing (operation 2602). The rotationmay be performed by an actuator. Rotating the unfixed portion may allowfor a longer wingspan in the flight position than in the foldedposition. Rotating the unfixed portion may allow for improvedaerodynamic performance of the wing in the flight position and may allowfor use of the aircraft at airports that may require a smaller wingspanwhen in the folded position. Method 2600 may include holding a rotatingportion of a latch assembly by a first portion of the wing, the firstportion may be one of the fixed portion and the unfixed portion(operation 2604). The unfixed portion may include a wingtip and thefixed portion may include a wing box. Holding the rotating portion ofthe latch assembly may allow the latch assembly to secure the unfixedportion of the wing to the fixed portion of the wing when in the flightposition. The latch assembly may be a cam latch. Holding the rotatingportion may include the rotating portion being: connected to the fixedportion of the wing, and being configured as a cam. The cam may be:substantially cylindrically shaped and may include a slot.

Method 2600 may include holding a secured portion of the latch assemblyby a second portion of the wing, the second portion may be the other ofthe fixed portion and the unfixed portion (operation 2606). Holding thesecured portion of the latch assembly may allow the latch assembly tosecure the unfixed portion of the wing to the fixed portion of the wingwhen in the flight position. Holding the secured portion may include thesecured portion including a group of openings. The group of openings maybe semicircular shaped with a first diameter that is larger than asecond diameter of a securing portion of the cam.

Method 2600 may include receiving a secured portion of the wing by aslot of a rotating portion of the latch assembly (operation 2608).Receiving the secured portion of the wing by the rotating portion mayallow the rotating portion to transition from the open position to aclosed position. Receiving a secured portion may include passing a sideof the secured portion from outside one point on a perimeter of the camthrough the slot in the cam to outside an opposing point on theperimeter of the cam, the side being nearest the fixed portion, and theslot being a substantially hemispherical indentation in the camconfigured to allow the side to pass through the slot.

Method 2600 may include rotating the rotating portion of the latchassembly, via a latch actuator, between the open position and a closedposition (operation 2610). Rotating the rotating portion between theopen position and the closed position may allow the rotating portion tosecure the secured portion.

Method 2600 may include securing a secured portion of the latch assemblyby a securing portion of the rotating portion when the rotating portionmay be in the closed position (operation 2612). Securing the securedportion of the latch assembly by a securing portion of the rotatingportion may prevent movement of an unfixed portion of a wing withrespect to a fixed portion of the wing. The securing portion of therotating portion may be the securing portion of the cam.

Method 2600 may include preventing, via a securing portion of therotating portion, rotation of the unfixed portion when the wing is inthe flight position (operation 2614). The securing portion of therotating portion may be substantially a hemisphere of the cam, thehemisphere being without a slot.

Method 2600 may include engaging the rotating portion by a lock of thelatch assembly when the rotating portion is in the closed position(operation 2616). The lock may allow the rotating portion to transitionfrom the open position to the closed position when the lock may be in adisengaged position.

Method 2600 may include preventing rotation of the rotating portion bythe lock when the lock is engaged (operation 2618). Preventing rotationof the rotating portion by the lock may ensure that the latch assemblymay remain in the closed position when the wing may be in the flightposition.

Method 2600 may include exerting a force, via a spring, on an arm of thelock to engage a notch in a collar of the cam with the arm (operation2620).

Illustrative embodiments of the disclosure may be described in thecontext of aircraft manufacturing and service method 2700 as shown inFIG. 27 and aircraft 2800 as shown in FIG. 28. Turning first to FIG. 27,an illustration of an aircraft manufacturing and service method isdepicted in accordance with an illustrative embodiment. Duringpre-production, aircraft manufacturing and service method 2700 mayinclude specification and design 2702 of aircraft 2800 in FIG. 28 andmaterial procurement 2704.

During production, component and subassembly manufacturing 2706 andsystem integration 2708 of aircraft 2800 in FIG. 28 takes place.Thereafter, aircraft 2800 in FIG. 28 may go through certification anddelivery 2710 in order to be placed in service 2712. While in service2712 by a customer, aircraft 2800 in FIG. 28 is scheduled for routinemaintenance and service 2714, which may include modification,reconfiguration, refurbishment, and other maintenance or service.

Each of the processes of aircraft manufacturing and service method 2700may be performed or carried out by a system integrator, a third party,and/or an operator. In these examples, the operator may be a customer.For the purposes of this description, a system integrator may include,without limitation, any number of aircraft manufacturers andmajor-system subcontractors; a third party may include, withoutlimitation, any number of vendors, subcontractors, and suppliers; and anoperator may be an airline, a leasing company, a military entity, aservice organization, and so on.

With reference now to FIG. 28, an illustration of an aircraft isdepicted in which an illustrative embodiment may be implemented. In thisexample, aircraft 2800 is produced by aircraft manufacturing and servicemethod 2700 in FIG. 27 and may include airframe 2802 with plurality ofsystems 2804 and interior 2806. Examples of systems 2804 include one ormore of propulsion system 2808, electrical system 2810, hydraulic system2812, and environmental system 2814. Any number of other systems may beincluded. Although an aerospace example is shown, different illustrativeembodiments may be applied to other industries, such as the automotiveindustry.

Apparatuses and methods embodied herein may be employed during at leastone of the stages of aircraft manufacturing and service method 2700 inFIG. 27.

In one illustrative example, components or subassemblies produced incomponent and subassembly manufacturing 2706 in FIG. 27 may befabricated or manufactured in a manner similar to components orsubassemblies produced while aircraft 2800 is in service 2712 in FIG.27. As yet another example, one or more apparatus embodiments, methodembodiments, or a combination thereof may be utilized during productionstages, such as component and subassembly manufacturing 2706 and systemintegration 2708 in FIG. 27. One or more apparatus embodiments, methodembodiments, or a combination thereof may be utilized while aircraft2800 is in service 2712 and/or during maintenance and service 2714 inFIG. 27. The use of a number of the different illustrative embodimentsmay substantially expedite the assembly of and/or reduce the cost ofaircraft 2800.

The flowcharts and block diagrams in the different depicted illustrativeembodiments illustrate the architecture, functionality, and operation ofsome possible implementations of apparatuses and methods in anillustrative embodiment. In this regard, each block in the flowcharts orblock diagrams may represent a module, a segment, a function, and/or aportion of an operation or step.

In some alternative implementations of an illustrative embodiment, thefunction or functions noted in the blocks may occur out of the ordernoted in the figures. For example, in some cases, two blocks shown insuccession may be executed substantially concurrently, or the blocks maysometimes be performed in the reverse order, depending upon thefunctionality involved. Also, other blocks may be added in addition tothe illustrated blocks in a flowchart or block diagram.

The description of the different illustrative embodiments has beenpresented for purposes of illustration and description, and is notintended to be exhaustive or limited to the embodiments in the formdisclosed. Many modifications and variations will be apparent to thoseof ordinary skill in the art. Further, different illustrativeembodiments may provide different features as compared to otherillustrative embodiments. The embodiment or embodiments selected arechosen and described in order to best explain the principles of theembodiments, the practical application, and to enable others of ordinaryskill in the art to understand the disclosure for various embodimentswith various modifications as are suited to the particular usecontemplated.

What is claimed is:
 1. A method of folding and unfolding a wing, themethod comprising: rotating an unfixed portion of the wing with respectto a fixed portion of the wing between a flight position of the wing anda folded position of the wing; controlling, via a rotating portion of alatch assembly on the fixed portion of the wing, connecting the unfixedportion to the fixed portion; securing, a secured portion, comprising aT-shaped end, of the latch assembly in a securing portion of the unfixedportion of the wing; receiving the secured portion by a slot in a barrelof the latch assembly; and rotating, between an open position of thelatch assembly and a closed position of the latch assembly, the rotatingportion of the latch assembly, via moving the barrel, between an openposition and a closed position wherein securing the secured portion ofthe latch assembly by the securing portion of the rotating portionfurther comprises an end of the barrel comprising a notch engaging anarm.
 2. The method of claim 1, further comprising: securing the securedportion of the latch assembly by a securing portion of the rotatingportion via moving the rotating portion to the closed position; andpreventing, via the securing portion of the rotating portion, rotationof the unfixed portion when the wing is in the flight position.
 3. Themethod of claim 1, further comprising: engaging the rotating portion bya lock of the latch assembly after moving the rotating portion to theclosed position; and preventing rotation of the rotating portion byengaging the lock.
 4. The method of claim 1, wherein the fixed portioncomprises a wing box of the wing and the unfixed portion comprises awingtip of the wing.
 5. The method of claim 1, further comprisingconfiguring the latch assembly as a barrel latch.
 6. The method of claim1, further comprising: the rotating portion: connecting to an outer lugon the fixed portion of the wing: and being configured as the barrel;and the secured portion comprising an inner lug connecting to theunfixed portion.
 7. The method of claim 6, further comprising the barrelbeing substantially cylindrically shaped.
 8. The method of claim 1,further comprising the fixed portion of the wing comprising a latchactuator connecting to an outer lug retaining the barrel.
 9. The methodof claim 1, further comprising the arm connecting to a rod connecting toa lock actuator.
 10. The method of claim 9, further comprising: exertinga force, via the lock actuator, on the arm, acting as a lock, andengaging the notch with the arm.
 11. An apparatus comprising: a fixedportion of a wing; the unfixed portion of the wing configured to rotatebetween a folded position of the wing and a flight position of the wing;the fixed portion of the wing configured to hold a rotating portion of alatch assembly of the wing; and the unfixed portion of the wingconfigured to hold a secured portion of the latch assembly of the wing,the latch assembly configured to prevent rotation of the unfixed portionof the wing with the wing in the flight position, the latch assemblycomprising the rotating portion: configured to rotate between: an openposition, and a closed position; being a barrel that extends through anouter lug connecting to the unfixed portion of the wing; and comprising: a slot configured to receive the secured portion of the latchassembly, a securing portion configured to secure the secured portion ofthe latch assembly with the latch assembly in the closed position theslot comprising a first diameter width that is larger than a secondwidth of the slot in the securing portion of the barrel, such that thesecured portion fits, with the latch assembly in the open position, intothe barrel through the first width; and the second width of the slotcomprising a size configured to stop a rotation of the barrel at theclosed position of the latch assembly via a contact with a side of thesecured portion.
 12. The apparatus of claim 11, the latch assemblyfurther comprising a lock configured to: engage the rotating portionwhen the rotating portion is in the closed position; and preventrotation of the rotating portion when the lock is in an engagedposition.
 13. The apparatus of claim 11, wherein the fixed portioncomprises a wing box of the wing and the unfixed portion comprises awingtip of the wing.
 14. The apparatus of claim 11, wherein the securedportion comprises a T-shaped end, the slot of the rotating portion beingconfigured to allow the T-shaped end to fit into the rotating portionwith the rotating portion in the open position, and the securing portionof the rotating portion configured to secure the secured portion by therotating portion with the rotating portion in the closed position. 15.The apparatus of claim 14, further comprising the barrel beingsubstantially cylindrically shaped and comprising the slot, and thesecuring portion, formed thereby, of the rotating portion.
 16. A systemfor improving a fuel efficiency of an aircraft, the system comprising: afirst wingspan of the aircraft configured to expand beyond a lengthallowed for ground operation of the aircraft at an airport; and a wingfold system, located within a wing such that the wing fold systemcomprises a latch assembly of a size that precludes a need to add anythickness and any fairing to a shape of the wing, the wing fold systemconfigured to reduce the first wingspan of the aircraft to a secondwingspan of the aircraft, the second wingspan being within the lengthallowed, such the latch assembly comprises a rotating portion thatcomprises a barrel that comprises a slot, connected to a fixed portionof the wing and configured to secure a T-shaped secured portionconnected to an unfixed portion of the wing and an end that comprises anotch configured to engage an arm.
 17. The system of claim 16 furthercomprising the wing fold system configured to preclude a change, due tothe latch assembly within the wing of the wing fold system, of across-sectional outline of the wing, such that the wing fold systemcomprises a secured portion configured to engage the rotating portionthat comprises the slot and a securing portion.